Portable scale



FIG. 1 is a top front perspective view of a portable _scale showing my new design;

FIG. 2 is a right side elevation thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a front elevation thereof;

FIG. 5 is a bottom plan view thereof; and

FIG. 6 is a rear elevation thereof. 

The ornamental design for a portable scale, substantially as shown and described. 